Ultrasound has found wide clinical diagnostic acceptance, with portable systems already in use for triage in urgent care. We propose to radically improve access to high-quality imaging for detection of Abdominal Aortic Aneurysms, Trauma (FAST exam) and Pulmonary Edema through two point-of-care developments: Device A: a hand-held phased-array system which connects via USB to a commodity tablet for its display and power. Device B: a telemedicine phased-array which can be operated by an untrained user, and generates volume data for remote interpretation. Device A has a low enough cost to be broadly deployed to urgent-care physicians and paramedics with basic ultrasound skills. Device B is entirely operator- independent and can be used by untrained individuals in rural, aviation, disaster-relief and military settings. A remote physician viewing te volume data Device B acquires will make the diagnosis. To deliver these medical benefits we plan to bring together innovations in: Transducers, to substantially decrease system power consumption. We propose using a recently developed micromechanical (MEMS) device to achieve this. Image reconstruction. Our mathematical approach differs from the beam formation in use in standard ultrasound systems and enables compact, low-cost electronics while maintaining high image quality. System design, to achieve a product cost which will significantly broaden access to ultrasound imaging in the three target applications. In Phase I, Device A's design will be risk-reduced and specified. The goal of Phase II is to produce and clinically evaluate a prototype. The technology developed in Phases I and II will be directly applied to commercialization of Device A and Device B.